What is Chagas disease (spread by 'kissing bugs')?

Aug. 5, 2014
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"Kissing bug" / University of Arizona

by Jolie Lee, USA TODAY Network

by Jolie Lee, USA TODAY Network

"Kissing bugs" - or triatomine bugs - are blood-sucking insects that can transmit the life-threatening Chagas disease to humans.

Chagas is a little-known disease that's getting more attention with the USA's changing population.

"We have more and more immigrants coming who are at risk," said Sue Montgomery, an epidemiologist with the CDC's Division of Parasitic Diseases and Malaria. "Awareness among health care providers has just lagged."

The disease can be asymptomatic or produce mild symptoms after a few weeks or even months after infection, including fever or swelling around where the parasite entered the skin.

People may also be susceptible to allergic reactions.

"The first bite may only leave a small welt and is rarely dangerous," reports The Arizona Republic. "On subsequent bites, however, an allergy can develop and cause a wide variety of symptoms that include flushed skin, hives, rashes, wheezing, nausea and vomiting."

In the most severe cases, although rare, the infection can cause inflammation of the heart or brain, according to the CDC. Complications include abnormal heartbeats, a dilated heart or a dilated esophagus or colon, "leading to difficulties eating or passing stool," according to the CDC.

Who is most susceptible to infection?

People from Latin America have a greater chance of getting the disease. An estimated 8 million people have Chagas in Mexico, Central America and South America, according to the CDC.

There have only been 23 cases of someone contracting Chagas in the USA since 1955, Montgomery said. Almost all people with the disease in the USA have been infected outside of the country.

But there is evidence people in the USA are getting infected beyond the reported numbers, said Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine.

Hotez is researching Chagas transmission in Texas and finding "anecdotal cases," he said.

The disease causes 21,000 deaths a year in Mexico, Central and South America, according to a 2010 University of Arizona study.

Hotez and colleagues have estimated the cost of Chagas in the USA and Canada total $864 million per year, according to a 2013 report.

Where are kissing bugs found in the USA?

Bugs have been found in the southern half of the USA, according to the CDC.

Some recent findings:

â?¢ Arizona: A 2010 University of Arizona report estimates that 40% of the state's kissing bugs carry a parasite strain related to the Chagas disease but rarely transmit the disease to humans. The Arizona Department of Health Services reported one Chagas disease-related death in 2013, reports The Arizona Republic.

â?¢ Arkansas: A woman in Arkansas found a bug in her home and posted it on social media. "It was big, it was ugly, it was the size of a dime," said Terry Summers of Jonesboro, Ark., in an interview with THV-TV in Little Rock.

â?¢ Texas: A study in 2013 by Texas A&M researchers found 8.8% of dogs at seven shelters in Texas have the parasite. Humans cannot get the disease from dogs, but the study shows that dogs are exposed to "bugs carrying parasites in their environment," Montgomery said.

How is the parasite transmitted?

"Kissing bugs" get their name from their preference to bite around people's eyes and mouths. But it's not the bite that transmits the parasite -- it's in the bugs' feces.

People can also become infected through an organ transplant from an unscreened organ donor or eating uncooked food that contains infected bugs' feces, according to the CDC. Blood donations have been screened for Chagas since 2007, which has eliminated the risk of transmission that way, Montgomery said.

Can Chagas be prevented?

There is no vaccine for Chagas disease.

Two drugs are available for treatment. These drugs have not been approved by the Food and Drug Administration, but the CDC makes them available under protocols to physicians who are caring for a Chagas patients, Montgomery said.

Also, the best way to avoid Chagas is to avoid the kissing bug. They are found in "houses made from materials such as mud, adobe, straw, and palm thatch," the CDC states. The agency recommends avoiding sleeping in these types of shelters, keeping woodpiles away from homes and using insect repellent.